When you send a long prompt to Copilot in Microsoft 365, the service may return an HTTP 502 Bad Gateway error. This error appears as a blank screen or a browser error page instead of Copilot’s response. The cause is a timeout or overload on the backend server that processes your request. This article explains … Read more
Official documentation checked October 14, 2026. AADSTS700016 means Microsoft Entra ID could not find the requested application in the directory or tenant used by the authentication request. When it appears while opening Copilot, the first task is to identify that application and tenant—not to create an enterprise application using a supposed universal Copilot ID. Several … Read more
When you use Copilot in Microsoft Teams, a HTTP 504 Gateway Timeout error suddenly appears and stops your workflow. This error means the upstream server that processes your Copilot request did not respond within the allowed time window. The root cause is usually a network bottleneck, a misconfigured firewall, or an overloaded Microsoft 365 backend … Read more
Official documentation checked October 14, 2026. If Copilot in Microsoft Edge repeatedly reports an expired token, record the exact message before changing settings. A repeated sign-in failure can involve the account, browser session, organization policy, or service. The message alone does not prove that Windows credentials are corrupt, and a browser repair should not start … Read more
Official documentation checked October 14, 2026. AADSTS90072 is an identity and MFA-context error, not proof that Copilot needs a blanket cross-tenant trust change. Microsoft’s current definition says the external account is missing from the tenant being accessed, preventing satisfaction of that tenant’s MFA requirements; a synchronization source-anchor mismatch is another documented possibility. Start by checking … Read more
When you try to sign in to Microsoft Copilot, you may see an error message about a WS-Federation sign-in failure. This error prevents Copilot from connecting to your Microsoft 365 tenant and blocks all Copilot features. The failure typically occurs because of a misconfigured identity provider, an expired federation certificate, or an incorrect domain federation … Read more
Official documentation checked October 14, 2026. If organizational Copilot works on a computer but not on a phone, first identify the failed sign-in and its policy result. Do not replace device compliance with MFA, trust an entire mobile carrier, or exclude Copilot from security policies merely to remove the error. The correct remedy is usually … Read more
When you try to sign in to Copilot in Microsoft 365, you may see error AADSTS50105. This error means the user account is not assigned to the required license or application role. The error prevents access to Copilot features in apps like Word, Excel, and Teams. This article explains the root cause and provides step-by-step … Read more
When you upload a file to Copilot in Microsoft 365, you may see an HTTP 413 error that stops the process. This error means the server rejected the file because its size exceeds a defined limit. The root cause is typically a restriction in the Microsoft 365 tenant configuration or a local proxy setting that … Read more
Official documentation checked October 14, 2026. A “Service Principal Not Found” message while administering Copilot needs investigation of the actual directory object named by the failing operation. The banner alone is not enough to identify a universal missing “Copilot” application, and it does not justify creating one with an ID copied from an unrelated example. … Read more